In a conventional electronic apparatus having an imaging function, such as a digital still camera or a digital video camera, a solid-state imaging device like a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) image sensor is used. A solid-state imaging device has pixels each including a combination of a photodiode (PD) that performs photoelectric conversion and transistors, and an image is formed in accordance with pixel signals that are output from the pixels arranged in a two-dimensional fashion. Further, the pixel signals output from the pixels are subjected to AD conversion in parallel by analog-to-digital (AD) converters arranged for the respective columns of the pixels, for example, and the pixel signals are then output.
Also, there have been various recently suggested techniques for capturing a high dynamic range (HDR) image that has a dynamic range widened by an imaging method by which signals generated in different exposure times are combined.
For example, Patent Document 1 discloses a solid-state imaging device that drives a pixel including first and second charge storage units so that an electric charge equal to or smaller than the saturation charge amount of the first charge storage unit is stored in the first charge storage unit, and an electric charge exceeding the saturation charge amount of the first charge storage unit is stored in the first and second charge storage units. With this imaging device, it is possible to increase the HDR ratio while improving the signal-to-noise ratio (SNR), by performing HDR combining in three stages: low illuminance, medium illuminance, and large illuminance.